Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
  • C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
  • C08G18/7628—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring containing at least one isocyanate or isothiocyanate group linked to the aromatic ring by means of an aliphatic group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
  • C08G18/3855—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur
  • C08G18/3876—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur containing mercapto groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/67—Unsaturated compounds having active hydrogen
  • C08G18/671—Unsaturated compounds having only one group containing active hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/67—Unsaturated compounds having active hydrogen
  • C08G18/671—Unsaturated compounds having only one group containing active hydrogen
  • C08G18/672—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
  • C08G18/673—Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen containing two or more acrylate or alkylacrylate ester groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L81/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing sulfur with or without nitrogen, oxygen or carbon only; Compositions of polysulfones; Compositions of derivatives of such polymers
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses

Definitions

• This invention relates-to a resin composition having high-speed polymerizability and a plastic lens obtained therefrom.
• the lens obtained from the composition of the present invention has a refractive index (n d ) of at least 1.59.
• Plastic lenses are lightweight and non-fragile compared with inorganic glass lenses so that they are finding rapidly increasing utility as eyeglass lenses, camera lenses or optical elements in recent years.
• Resins widely employed these days for such purposes include a radical polymerization product of diethylene glycol bis(allyicarbonate) (for example, "CR-39", trade name; product of PPG).
• This resin has various advantages such as excellent impact resistance, lightweight, superb dyeability, and good workability such as good cutting and grinding machinability.
• Its refractive index is 1.50 which is lower than the refractive index (1.52) of inorganic glass.
• refractive index of the plastic lens which unavoidably increases its central thickness or peripheral thickness, resulting in an overall large thickness. There is accordingly an outstanding desire for the development of a lens resin having a still higher refractive index.
• the present inventors have already proposed a plastic lens made of a sulfur-containing urethane resin which can be prepared by the polymerization of a polyisocyanate and a polythiol (Japanese Patent Publication No. 15249/1992).
• the resin has a high refractive index (n d ) of 1.57 or higher and also has various advantages like CR-39 so that it is used widely now.
• the resin is accompanied with the problem that it requires long polymerization time and any attempt to complete the polymerization in a short time tends to result in a lens with optical unevenness (striae).
• the present inventors have also proposed a composition which contains, in addition to the sulfur-containing urethane resin, a hydroxyl- or mercapto-containing acrylate, methacrylate or styrene (Japanese Patent Laid-Open No. 96208/1989).
• a lens resin When a lens resin is prepared using the composition, it has an improved thermal deformation temperature.
• the resin composition develops optical unevenness (striae) and in addition, cannot always provide a sufficient refractive index.
• a composition capable of providing a plastic lens with an improved thermal deformation temperature and improved surface hardness in a similar manner has also been proposed (Japanese Patent Laid-Open No. 25240/1993).
• This composition has a relatively high refractive index but is accompanied with the drawback that due to the use of tolylene diisocyanate, it will be tinged yellow by ultraviolet rays in sun light as time goes on.
• An object of the present invention is to provide a sulfur-containing urethane resin composition having high-speed polymerizability add a refractive index (n d ) of at least 1.59 and does not develop yellowing with the passage of time.
• the present inventors have conducted extensive research with a view toward developing a resin composition which has a refractive index (n d ) of 1.59 or higher and also high-speed polymerizability without the need for tolylene diisocyanate.
• n d refractive index
• use of a polythiol having at least 3 mercapto groups makes it possible to provide the polymerized resin with heat resistance sufficiently to withstand, as a plastic lens, heat at the time of polishing or dyeing; use of a polythiol having a sulfur content of 40 wt.
• the present invention therefore provides a high-speed polymerizable resin composition which comprises:
• R represents a hydrogen atom or a methyl group, and ii) a polythiol having at least 3 mercapto groups per molecule and a sulfur content of at least 40 wt. %;
• a compound which has, in a molecule, at least one functional group selected from a hydroxyl group or a mercapto group and at least one functional group selected from an acrylic group, a methacrylic group or a styrylic group, said composition containing isocyanato groups, mercapto groups and hydroxyl groups at an NCO/(SH+OH) equivalent ratio of from 0.50 to 1.50 and being capable of providing a lens resin having a refractive index (n d ) of at least 1.59.
• the present invention also provides a high refractive-index plastic lens obtained by thermal polymerization of the above composition.
• the resin composition according to the present invention does not develop an optically uneven part (striae) in the resulting lens even when the polymerization time is shortened considerably compared with the conventional thermal polymerization of a polyisocyanate and a polythiol alone, does not undergo yellowing with the passage of time and in addition, has high pencil hardness. It is therefore useful as a resin for eyeglass lenses, camera lenses or optical elements.
• aromatic polyisocyanate represented by formula (I) usable in the present invention include compounds such as o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 1,3-bis( ⁇ , ⁇ -dimethylisocyanatomethyl)benzene and 1,4-bis( ⁇ , ⁇ -dimethylisocyanatomethyl)benzene. They may be used either singly or in combination.
• Illustrative of the compound having at least 3 mercapto groups per molecule and a sulfur content of 40 wt. % or greater include polythiol compounds such as 1,2-bis(mercaptoethyl)trithioglycerin, pentaerythrithiol, 1,2,4-tris(mercaptomethyl)benzene and 1,3,5-tris(mercaptomethyl)benzene.
• Examples of the compound which has, in a molecule, at least one functional group selected from a hydroxyl group or a mercapto group and also at least one functional group selected from an acrylic group, a methacrylic group or a styrylic group include compounds obtained by subjecting an epoxy or thiiran group to ring-opening with acrylic or methacrylic acid, such as hydroxyethyl acrylate or hydroxyethyl methacrylate; compounds obtained by subjecting phenylglycidyl ethers to ring-opening with acrylic or methacrylic acid, such as 3-phenoxy-2-hydroxypropyl acrylate and 3-phenoxy-2-hydroxypropyl methacrylate; ring-opened products of 2,4-dibromophenylglycidyl ethers with acrylic or methacrylic acid; ring-opened products of bisphenol A diglycidyl ethers with acrylic or methacrylic acid; and compounds such as 1,3-bis(acryloyl)glycer
• the high-speed polymerizable resin composition according to the present invention which is suitable for use in the production of a high refractive-index lens, can be prepared using in combination:
• Use of the component b) in an amount smaller than 10 parts by weight cannot sufficiently improve the surface hardness.
• An amount greater than 30 parts by weight tends to result in a lower refractive index.
• the ratio of an equivalent amount of SH and OH groups to an equivalent amount of NCO groups falls within the range of from 0.50 to 1.50, preferably from 0.75 to 1.25 in terms of NCO/(SH+OH). Ratios smaller than 0.50 or greater than 1.50 tend to make it difficult to furnish a resin with high rigidity.
• the composition is subjected to thermal polymerization.
• a polymerization catalyst such as a tin compound, e.g., dibutyltin dilaurate or dimethyltin dichloride, morpholine or dimethylaminobenzene may be added in an amount of 0.001-1.0 wt. % based on the total amount of the resin composition.
• a peroxide such as benzoyl peroxide, dicumyl peroxide or di-t-butylperoxide can be added in an amount of 0.01-3.0 wt. % based on the total amount of the resin composition.
• the high-speed polymerizable resin composition according to the present invention is polymerized by cast polymerization or the like, it is desired to treat, in advance, the surface of a mold with wax or a silicone- or fluorine-type external mold releasing agent; or to add a silicone- or fluorine-type nonionic surfactant or an anionic surfactant such as an acidic phosphate ester beforehand to the composition of the present invention as an internal addition type mold releasing agent.
• the internal-addition type mold releasing agent it is desired to add the agent at 10-20,000 ppm to the composition.
• additives such as ultraviolet absorbers, antioxidants, coloring preventatives and/or fluorescent dyes to the composition of the present invention so that the resin obtained by the polymerization of the composition can have improved weatherability.
• At least one of pentaerythritol tetrakis(thioglycolate), pentaerythritol tetrakis( ⁇ -mercaptopropionate), trimethylolpropane tris(thioglycolate) and trimethylolpropane tris( ⁇ -mercaptopropionate) may be added to an extent not impairing the advantages of the present invention so as to permit the target resin to have improved dyability in a dyeing bath of a disperse dye.
• it is preferred to control the amount of the additives lower than 20 parts by weight in the composition to retain the high refractive index.
• a polymerization catalyst, internal-addition type mold releasing agent, ultraviolet absorber and/or the like are(is) optionally added to the composition of the present invention or the composition which has been subjected to preliminary polymerization.
• the liquid so obtained is cast in a glass or metal mold equipped with spacers made of an ethylene-vinyl acetate copolymer, polyvinyl chloride or the like.
• the liquid in the mold is placed in a thermal polymerization oven, thermally polymerized and then cooled, whereby moldings of a desired shape can be obtained.
• the time required for the fabrication of a lens from the resin composition according to the present invention is as short as 1/5-1/2 of the time needed for the fabrication of a lens, which has the same strength and is free of optical unevenness (striae), by polymerizing an ordinary sulfur-containing urethane lens resin.
• a lens obtained by curing the composition of the present invention has improved surface hardness compared with that obtained by polymerizing a composition composed only of a polyisocyanate and a polythiol.
• Each lens was ground by a spherical grinder for eyeglass lenses and the lens having a good ground surface was ranked as good (A).
• Each lens was measured by an optical strain indicator.
• the lens free of strain was ranked as (A) and the lens with strain was ranked as (B).
• Each lens was set in a weather-o-meter equipped with a sunshine carbon arc lamp. Upon an elapsed time of 48 hours, the lens was taken out of the weather-o-meter and was compared in color hue with the same lens resin before the test.
• the mold was formed of a glass mold equipped with a gasket.
• the mixture in the mold was heated from 45° C. to 130° C. over three hours for thermal polymerization.
• the polymer so obtained was heated at 130° C. for one hour, cooled and then released from the mold, whereby a lens was obtained.
• the lens so obtained had a refractive index of 1,595, Abbe's number of 38 and specific gravity of 1.33. It had good,grinding machinability, free of optical strain and had a pencil hardness of 3H.
• Example 2 As in Example 1, a lens was fabricated from each of the compositions shown in Table 1. The results of an evaluation of the lens are presented in Table 2.
• Example 2 As in Example 1, a lens was obtained. The properties of the lens so obtained are presented in Table 2.
• Example 2 As in Example 1, a lens was obtained. The properties of the lens so obtained are presented in Table 2.
• Example 2 In a similar manner to Example 1 except that 188 parts (1.0 mole) of m-xylylene diisocyanate, 195 parts (0.4 mole) of pentaerythritol tetrakis(3-mercaptopropionate) and 52 parts (0.4 mole) of hydroxyethyl methacrylate were used instead, a lens was fabricated. The properties of the lens so obtained are presented in Table 2.
• Example 2 In a similar manner to Example 1 except that 188 parts (1.0 mole) of m-xylylene diisocyanate, 136 parts (0.80 mole) of 1,3-xylylenedithiol and 102 parts (0.20 mole) of bisphenol A diglycidyl ether which had been ring-opened with methacrylic acid were used instead, a lens was fabricated. The properties of the lens so obtained are shown in Table 2.
• Example 2 In a similar manner to Example 1 except that 500 ppm of "Tinuvin® PS" (trade name for an ultraviolet absorber; product of CIBA-GEIGY AG) were added further to the composition, a lens was fabricated. The color hue of the lens after the weatherability test was compared with that before the test. As a result, no change (A) was recognized. In addition, it was free of optical strain.
• Teuvin® PS trade name for an ultraviolet absorber
• Example 2 In a similar manner to Example 1 except that 188 parts (1.0 mole) of m-xylylene diisocyanate were replaced by a mixture of 94 parts (0.5 mole) of m-xylylene diisocyanate and 87 parts (0.5 mole) of 2,4-tolylene diisocyanate, and 500 ppm of "Tinuvin® PS" were added to the composition, the mixture was treated. An exothermic reaction then occurred and the mixture became so thick so that fabrication of a lens was hardly feasible.
• Example 2 In a similar manner to Example 1 except that mixing was conducted while cooling the mixture at -5° C. or lower, a lens was fabricated. The color hue of the lens after the weatherability test was compared with that before the test. As a result, marked yellowing (B) was observed. In addition, optical strain of the lens was eminent.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Polyurethanes Or Polyureas (AREA)
• Eyeglasses (AREA)

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Citations (10)

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• 1994
  • 1994-12-01 US US08/352,811 patent/US5578658A/en not_active Expired - Lifetime
  • 1994-12-07 DE DE69418291T patent/DE69418291T2/de not_active Expired - Lifetime
  • 1994-12-07 EP EP94309122A patent/EP0659790B1/de not_active Expired - Lifetime
  • 1994-12-19 KR KR1019940034893A patent/KR0165863B1/ko not_active IP Right Cessation
  • 1994-12-20 CN CN94119109A patent/CN1040651C/zh not_active Expired - Fee Related
• 1997
  • 1997-11-29 CN CN97125375A patent/CN1207501A/zh active Pending

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